wulfrun

On 30/12/2021 at 08:07, DhamR said:

I've also got the top truss thumb screw clashing with the red dot when the scope is collapsed which seems like a poor design decision...

I found this too, on a non-Virtuoso version. I've changed the finder since but I found you could just about move the finder forwards on its fixing far enough to avoid the locking thumbscrew.

13 minutes ago, Graviton1 said:

Thanks so much for the help everyone.

I think I am going to save a bit and go for the SW 150p dob, definitely seems to tick all the boxes for me. Will probably be back asking for help on collimation the day it arrives (😫) but thank you for all the advice!

Cheers,

Sam

Certainly not a poor choice. The 150P dob is an f/8 mirror so it's less critical on collimation and not too demanding on eyepieces either. I have the equivalent "tube" on a different mount and it performs very well and holds collimation well too. Unless you suspect there's something badly out I'd use it first chance and check collimation by a star-test on Polaris. Don't fiddle without good reason.

Pentax screw is m42 x 1, as you say. You'll need a Pentax m42 to Nikon adapter. The m42 x 0.75 is for (Tamron) Adaptall 2 and compatible lenses. Do check that the camera can "shoot without lens", if not it won't work.

I've vague recollections of the name Pentor from back in the day, I think they were a budget brand but you never know, it may be fine.

EDIT:  I see it may not focus to infinity anyway, as per  post above @davew

Fit a shoe (probably what you've called the bracket) to the "solid" part of the tube. Not the ideal place but you won't be the first to do it and I plan to do the same to mine at some point. It will mean drilling a couple of holes so you'll need to make sure no filings or swarf drops down the tube (ideally, remove the mirrors but I think it can be done without, with some care). Choose your position so it doesn't interfere with the guide rods, focuser etc and also the standard finder, if you're keeping it.

Is it possible to go out at this time of year, with a clear sky and NOT look at it? Doesn't matter if it's just your eyes, through binoculars or a telescope it's always worth a look. Especially through a telescope it's a definite "Wow!" object and there's always more to see.

12 minutes ago, Saggy said:

Perfect, OKay will go as sun setting. Won't be able to see it later I don't think as the more west it goes, the more Portsmouth will get in the way 😄

Will it be the same the day after boxing day?

THanks, Sarah

 

Near enough, yes. Each day (EDIT: night?) brings celestial events 4 minutes earlier (not totally accurate, nor for everything but close enough for most). So Jupiter rises AND sets about 4 minutes earlier. Eventually it'll set before dark until well into next year when it comes "back around", so it'll not be visible.

Do note that's not a totally accurate description but it's good enough. The sun and moon don't fit the description, for instance.

14 minutes ago, Saggy said:

Thanks - I'm assuming by SW you mean south west. THe only dark part of the beach is over on the east so I wonder if will be able to see it if only low down over the tall stuff in between because of the way it curves round. Will definitely try though and should be able to just do it if it's not too westerly.

THanks again 🙂 

Yes, south-west, it'll set even further to the west. You won't need the darkest skies for Jupiter so no problem with compromising the viewpoint. It'll be at its highest earlier (i.e. clearer view) so start looking as soon as it's dark enough - it'll be one of the first things visible as darkness falls.

5 minutes ago, Saggy said:

Okay perfect - so we can see still some things if we head off to the beach on Boxing day. So I'll look for Jupiter perhaps and work out when you are able 🙂

I can imagine the overwhelming aspect, even the campsite isn't quite so amazing as in the middle of the moors in the middle of the night - the sky is literally littered with stars without a space in between!!

THanks  🙂

 

There's always something to see on a clear night. Jupiter will be low down in the SW on boxing day, it'll set around 8pm. The view will likely not be very clear but it's unmistakable and you should see several of its moons (up to 4 are readily visible).

Brighter things such as the moon, Jupiter, Mars etc aren't so badly affected by light pollution, so they're always visible (at the right time of course). A telescope will always show vastly more than the naked eye too, even though you may struggle to get a specific object in view. In really dark places, it can also be difficult to see the constellations because your view is overwhelmed (nice problem to have though).

There are numerous phone apps that will allow you to point the phone at the sky and reveal what's in that area and potentially viewable. Some allow you to attach the phone to the scope and show you on-screen what it's pointed at, once set up correctly. Not deadly-accurate but can be helpful.

51 minutes ago, Saggy said:

I'm assuming it doesn't have to be perfectly level?

Approximately is good enough, it just needs to be level enough not to be unstable.

1 hour ago, Saggy said:

Ah okay, so cooling time not really that big a deal on the range i'm looking at even if have to learn how to collimate so possibly heritage range not completely out the question???

Thanks again, Sarah

The smaller Heritage scopes don't have provision for collimating the primary mirror, it's "factory set" and fixed. At least up to the 114 this is the case, I'm not sure about the 130 but the 150 and upwards have collimatable primaries. The secondary mirror can be adjusted on all but unless you mistreat it fairly badly it's not likely to go out of adjustment in a long time - and it should come set correctly.

All scopes work at their best when cooled to ambient temperature, it's not a case of they don't work before. A small scope cools more quickly (no surprise!).

Just now, teoria_del_big_bang said:

The positive switches, which are wired as you describe. are the most common but you can get negative switches as well which do pass the -ive through to the load rather than the _ive, just to confuse things.
This is ideally why a link to where it was bought from would help or a look at the terminals with a good close up image of the actual switch.
 

Steve

Good point so yes, it's important to know which he has. However, using the "wrong" one does only mean the illumination might not work. Negative earth has been the convention in automotive for many years and seems to be the most common in other low-voltage gear, including astro stuff (I think!)

If you have a test meter and aren't sure which terminal is which on the switch you can find out as follows. Remove the switch entirely, or at least disconnect all terminals. Set your test meter to "ohms" and short the test leads together, it should then read roughly zero. Now connect across two terminals of the switch and see which pair gives zero (ish) with the switch "on" and "infinity" with it "off" (digital meters usually display a "1" or "O/L" or similar for infinity reading). These two are the two you need to connect in the power line. The third will be "earth" for illumination BUT the switch MUST be in the positive side and not in the negative lead as per your original diagram. Switching the negative is unconventional and leaves the output with a permanent "live", this could come back to bite you (not literally, at only 12V!) in future. It may also fail to light an LED, if that's what it uses for illumination, if in the negative lead.

If the switch illuminates regardless of on or off, swap the incoming and outgoing power terminals (assuming you want it lit only for "on").

Odd way to wire it up! Conventional method would be negative direct to socket and positive to fuse, then on to switch, then on to socket. If the switch is a simple "spdt" type, the centre terminal connects to the incoming power (from fuse) and the switched side goes from either end terminal to the outlet socket - the choice depends which switch position you want "on" to be.

Be careful checking voltages with a test meter, they draw almost zero power so will still show a voltage even when there's a duff connection somewhere. Use a test lamp or connect an actual load once you are certain the polarity is correct, to be sure there's actual power.

EDIT: Agreed a photo of your switches would be helpful

Your picture is almost invisible on my screen, you may want to change it! It'd be an unusual tattoo, that's for sure.

The focuser should cope with 337g. I've used an Explore Scientific focal extender plus 20mm/68, combined weight 460g and it coped OK. Not the most sensible use and possibly some slight flex but I didn't find it problematic.

If you want the widest FOV, lowest power EP you could do worse than a 32mm Plössl (6.4mm exit pupil). A more expensive option might be something like an Explore Scientific 24mm/68 (4.8mm exit pupil) for just over 2-degree FOV, about the same as the 32mm Plössl would give.

9 minutes ago, Space Explorer said:

...I heard it is possible to see the apollo that landed with Neil Armstrong and I don't mean he will be there waving back, I mean the exact  point it landed, is this true? 

No, if you mean you can see any of the stuff they left behind. You have to remember you'll be looking through the earth's atmosphere, which is turbulent and not completely clear. No amateur scope gets anywhere near enough magnification, at least in part due to atmospheric limitations.

There is a 10" flex-tube go-to:

https://www.firstlightoptics.com/dobsonians/skywatcher-skyliner-250px-flextube-goto.html

One thing to bear in mind, you'll need additional eyepieces and since it's what's called a "fast" scope it will benefit from premium ones (meaning expensive). The eyepiece(s) supplied with most scopes are usually get-you-started types (= cheapos).

45 minutes ago, Space Explorer said:

It seems that dobsonians has clearest resolutions than any other telescopes, I wonder if their is a mak that uses dobsonian technology...

You seem to have got confused over this. The dobsonian is the method of mounting a scope tube, the "mount". It's a simple, cheap and sturdy mount but no-one sells one with anything other than a newtonian reflector on it (I think).

EDIT: not least because the eyepiece on a mak or refractor would end up in a very inconvenient place, unlike a newtonian.

Partly personal choice, not everyone gets on with zooms. The downside is that they give the least field of view (AFOV) at their lowest power so the Starguiders will outdo the BHZ, in that respect, at all except highest power. The upside is convenience of not swapping EPs. Usual advice is to get a low-power EP for maximum field-of-view to complement a zoom, e.g. 32mm Plössl.

Not sure of your scope details but BHZ + Barlow gives down to 4mm, which is maybe too much magnification?

Just to add to the comments above, your power connections are going to fail unless re-soldered properly. As the failed joint comes apart, it's really pot-luck what the outcome might be but it could be £££ so I'd re-do before serious usage. Looks a more secure power connector though!

How about a planisphere? Inexpensive and an "everlasting" calendar-based tool. Things like "Turn Left At Orion" seem to expect binoculars as a minimum. Not sure about others.

2 minutes ago, Captain Magenta said:

Haha I’m only drawing on my O-level too so highly unreliable also 😁😁. I did get an A and to this day I have no idea how. I was rubbish at it, hated it, and found the exam very difficult. I think they must’ve got some papers mixed up!

I can empathise with your sentiments, they echo mine! However, English has many words derived from Latin so it has its uses to have studied it (even reluctantly).

2 minutes ago, Captain Magenta said:

If Latin it’d depend whether it was 2nd declension or 4th declension, in which case the plurals would be Morpheii or Morpheus respectively. If Greek, I have no idea 😃

… the things one remembers from 45 years ago 🙄

Latin has the distinction of being my only exam failure (at O-level) so I stand corrected. I have found what Latin I managed to absorb to be useful at times but clearly it ain't up to snuff here!

"Morpheus" might sound like it's latin-derived and hence pluralised as "morphei". However, it's not, it's a made-up name based on a Greek root. As such, since it ends in "s", the plural ought to be made by adding "es" for "morpheuses".

Cf. Businesses, octopuses, buses etc.